Manually operable electric switch



Aug. 23, 1960 2,950,366

C. E. M ROBERTS ETAL MANUALLY OPERABLE ELECTRIC SWITCH 2 Sheets-Sheet 1 Filed Oct. 30, 1957 INVENTOR CHARLES E. Mc ROBERTS JOSEPH F PICK D FF LD BY 1% PATEN T AGEN T Aug. 23, 1960 c. E. MCROBEIRTS ET AL 2, 5

MANUALLY OPERABLE ELECTRIC SWITCH 2 Sheets-Sheet 2 Filed Oct. 30, 1957 INVENTOR.

CHARLES E Mc ROBERTS JOSEPH FRED lCK DUFF LD PATENT AGENT United States Patent MANUALLY OPERABLE ELECTRIC SWITCH Charles E. McRoberts, Toronto, Ontario, and Joseph F. Dulfield, Agincourt, Ontario, Canada, assignors to Amalgamated Electric Corporation, Limited, Toronto, Ontario, Canada Filed Oct. 30, 1957, Ser. No. 693,419-

7 Claims. (Cl. 200-68) This invention relates to manually operable electric switches and particularly to such switches adapted for household and other uses in which a relatively low A.C. current is sought to be interrupted.

There are many types of manually operable switches in use today. Generally, however, these switches suffer from one or more of the following disadvantages.

(1) They are inherently noisy to operate thereby requiring extraneous means for quieting,

(2) The quieting means required is subject to deterioration in usage,

(3) They are relatively expensive,

(4) They are relatively bulky.

It is a principal object of this invention therefor to provide a switch of the class described which will be quiet in operation while requiring no shock absorbing materials such as rubber or the like.

It is another object of this invention to provide such a switch as will tend to urge the operating handle away from the dead centre or stall position and thus prevent arcing and consequent deterioration of the contacts.

It is yet another object of the invention to provide such a switch as will be of simple construction and thus more economical having regard to the advantages thereof.

These and other advantageous objects .will .become apparent through a consideration of the following detailed description taken in conjunction with the attached drawings in which Figure 1 is a part section of a switch constituted so as to embody features of the invention and takenalong the line of a moving contact.

Figure 2 is a view similar to Figure 1 but sectioned so as to illustrate other features of the invention.

Figure 3 is an enlarged view, partly diagrammatic showing the control cam track and spindle, and v Figure 4 is an exploded perspective of the switch shown in Figures 1 to 3. l

The invention consists broadly in the provision of a switch comprising an insulating bottom. portion, an operating handle mounted therein, and an insulating cover portion adapted to retain the handle, the bottom portion being provided with a cam track on both sides thereof, a spindle actuable in said cam track, a cam connected to said handle adapted to open and close a contact upon actuation of the handle, and means on the handle adapted to engage the spindle to limit and control motion of the handle.

In greater detail, and referring now to the drawings, an insulating switch bottom portion 1 is provided. This portion may conveniently be formed from a conventional phenolic resin because of its insulating properties and excellent wear characteristics which are important insofar as concerns the cam track hereafter described.

The bottom portion 1 is provided with terminals 2, 2A for connection to electrical supply, terminal 2 being adapted to secure an electric wire to fixed terminal 13A ice and, terminal 2A being similarly adapted to secure a wire to fixed terminal 13b. A movable contact 12 is fixed to terminal 13b and adapted, when unloaded to contact terminal 13A at its free end to complete the electrical circuit between 2A and 2, and when loaded, to break the contact at 13A.

Moulded into the interior of both sides of the bottom portion 1, is a control track 17 which may best be seen by reference to Figures 2 and 3. This control track comprises an intermediate high point 18 and two downwardly inclined faces 4a and 4b leading to two low points 19a and 19b on either side thereof. The downwardly inclined portions are preferably arcs of circles of greater radius than the diameter of the spindles hereinafter described but of lesser radius of curvature than the arc of rotation of the handles hereinafter described. The base portion is also formed with a recess 10C on both sides thereof.

A handle member 8 is provided having transversely extending pivots 9 adapted to seat rotatably in the recess 10C. The handle is provided with an enlarged lower portion 8b (shown as substantially circular in Fig. 4) the pivots 9 being located about the axis of the horizontal diameter thereof.

A cylindrical recess 7 is provided in the bottom of the handle, and a compression spring 6 is placed in this recess; the bottom portion of this recess being transversely slotted as at 5 to receive a spindle 4 adapted to seat, at each end thereof, in the cam tracks 17 and to permit a limited reciprocation of the spindle shaft therein against the action of the spring.

The lower portion of the handle 8b carries a cam 11 adapted, upon appropriate movement of the handle, to engage contact 12 and move it out of contact with 13a thus breaking the circuit.

A cover plate 14, having a cut out portion to permit outward projection and oif-on movement of the operating handle, is provided with downwardly depending lugs 10A and 10B adapted to retain the spindle 9 in the bottom recess 10C.

The operation of the switch is as follows: Assuming that the projecting operating handle 8 is in the righthand position as viewed in Figures 1 and 2, the cam 11 is out of engagement with the contact 12, the spindle 4 is in the left valley of the control track 17, and there is minimum pressure on the spring 6. In this position, there exists a clearance between the neck of handle 8a and the inclined faces 15 of the out-out portion of the cover plate 14.

As the handle is moved from right to left, the lower portion of the handle below the pivots moves from left to right, the spindle following the configuration of the control track rises in the transverse slot 5 to increasingly load the spring until said spindle reaches the high point 18 of the track. Just prior to reaching this point, the

cam 11 engages the contact 12, moving it out of contact with 13a and breaking the circuit.

Movement of the. handle sufiicient to bring the spindle just past the high point of the control track causes the spring to urge the spindle down towards- 19b and take up a position at the selected extreme 4b and maintain the switch in the open position.

Movement again of the handle from left to right the spindle under the action of the spring, to roll to the lowest part of the track and take up a positive position either at 4a or 4b.

The relationship between cam 11 and contact 12 which is normally held in closed position under pressure with contact 133a because of restraint of member 12 by 13a, is such that the cam just engages the contact when the handle is in the position shown in Figure l at point A, i.e. when the spindle is just to the left of '18 in the control track. Continued force on the handle is necessary at this point to prevent the pressure of contact 12 on cam 11 in cooperation with spindle 4 from returning the handle to its original position, but the application of such a continued force past the dead centre point will permit spring 6 to urge the spindle 4 down the track 17 to position db.

Any over-travel of the switch handle beyond the position in which the spindle 4 rests at either 4a or 4b causes the spindle to rise, under the influence of the extensions to the cam track, beyond the points 19a and 19b to compress the spring and urge the spindle back to either of the positions 4a or 4b to prevent the neck 8a of the handle from striking inclined faces 15 to cause impact noise. Thus the control track and spindle provide a resilient and shock absorbing stop for the handle 8.

The placement of the spring within the handle, and the use of a substantially flat resilient contact strip gives rise to an important advantage in this invention. So far as is known, all A.C. switches previously known have comprised a handle control spring immediately beneath the handle, thus requiring additional depth to accommodate this spring, together with contact strips formed into shape. The construction of the present invention permits a substantial reduction in the depth of the assembly.

The invention may readily be adapted to other types of switches such as a three-way switch which in fact is the embodiment illustrated in Figure 4. In this case two resilient contacts 12 would be provided, one on either side of the switch box and the lower portion of the handle 8 provided with two cams 11 one adapted to operate each movable contact 12 in such a manner that when one contact was open the other Was closed and vice versa.

The rigidity of the resilient contact members will be increased, and the rate of lift relative to handle movement will be increased through the addition of ramps 20 to the resilent contact members adapted to be engaged by the contact engaging cam 11. These ramps may be seen by reference to Figures 1, 2, and 4.

The invention has been described with reference to a preferred embodiment and application. It is to be understood, however, that the detailed description given is offered by way of example, and should not be construed as limiting the invention. The invention is capable of many modifications without departing from the substance thereof, and such embodiments of the invention as come within the scope and purview of the appended claims are vention. 1

What we claim as our invention is:

1. An electric switch comprising an insulating bottom portion, an operating handle mounted in operative position therein and projecting therefrom, a cover portion adapted to retain the operating handle in operative position in the bottom portion, a line terminal means for attaching a current carrying wire, a load terminal means connecting said switch to a load, switching means to connect and disconnect said line terminal means and said load terminal means, cam tracks provided at each side of said bottom portion, each of said cam tracks including a mid-portion peak and valleys on opposite sides of said peak, a spindle engageable with said cam tracks, means on the handle independent of said spindle to be considered as part of this infor causing said switching means to connect said line terminal means and said load terminal means when said handle is operated in one direction to a first rest position with said spindle engaged in the valleys on one side of the peaks of said cam tracks, and for causing said switching means to disconnect said line terminal means and said load terminal means when said handle is operated in the other direction to a second rest position with said spindle engaged in the valleyson the other side of the peaks of said cam tracks, and retaining means on the handle engaging said spindle said retaining means including means biasing said spindle toward said cam tracks to limit and control movement of the handle in accordance with the movement of said spindle in following said cam tracks.

2. An electric switch as claimed in claim 1 wherein said switching means comprises a resilient member to bridge the line terminal means and the load terminal means, said resilient member being securely affixed to one of said terminal means to contact the other terminal means when said handle is operated in said one direction to said first rest position.

3. An electric switch as claimed in claim 2 wherein said resilient member comprises a substantially flat re silient strip provided with a ramp portion adapted to be engaged by the means on said handle when said handle is operated in said other direction to said second rest position.

4. An electric switch as claimed in claim 3 wherein said means for causing said switching means to contact said line terminal means and said load terminal means when said handle is operated in one direction to said first rest position and for causing said switching means to disconnect said line terminal means and saidload terminal means when said handle is operated in the other direction to said second rest position comprises a cam on the lowermost projecting portion of said handle and adapted when said handle is in said second rest position to enage said resilient strip to separate it from the other terminal means and when said handle is in the first rest position to release said resilient strip permitting said resilient strip to contact the other terminal means.

5. An electric switch as claimed in claim 4 wherein said retaining means on the handle comprises a transverse slot in the lowermost projecting portion of the handle in which said spindle is received and said biasing means comprises a compression spring located in a longitudinal cavity of said lowermost projecting portion adapted to urge said spindle away from the handle and into positive engagement with said cam tracks.

6. An electric switch comprising a housing having an opening in the top thereof, an operating handle mounted for pivotal movement about a pivot axis extending transversely of said housing with a manually engage able portion of said handle extending through said opening for moving said handle between first and second rest positions disposed at opposite extremes of pivotal movement of the manually engageable portion of said handle, a cam track radially spaced from said pivot axis, said cam track having a mid-portion forming a peak spaced a predetermined distance from said pivot axis and arcuate portions extending laterally on opposite sides of said mid-portion peak, said arcuate portions in extending laterally from said mid-portion peak curving radially away from said pivot axis for a first part thereof and curving radially toward said pivot axis for a second part thereof to form valley's on said cam track on opposite sides of said peak, a memberrnounted to be movable radially relative to said pivot axis, said member engaging said cam track to be moved thereby from one valley across said peak to the other valley upon movement of said operating handle between said first and second rest positions, said member yieldably limiting the extreme positions of said handle upon an gagement of said member with the curved second part of one of said arcuate portions, means urging said member towards said cam track, switching means Within said housing, terminal means for connecting opposite sides of said switching means in a circuit, and means on said handle independent of said member and engageable with said switching means for opening and closing said switching means in response to movement of said handle between said first and second rest positions respectively.

7. An electric switch comprising a housing having an opening in the top thereof, an operating handle mounted for pivotal movement about a pivot axis extending transversely of said housing with a manually engage able portion of said handle extending through said opening for moving said handle between first and second rest positions disposed at opposite extremes of pivotal movement of the manually engageable portion of said handle, a cam track radially spaced from said pivot axis, said cam track having a mid-portion forming a peak spaced a predetermined distance from said pivot axis and arcuate portions extending laterally on opposite sides of said mid-portion peak, said arcuate portions in extending laterally from said mid-portion peak curving radially away from said pivot axis for a first part thereof and curving radially toward said pivot axis for a second part thereof to form valleys on said cam track on opposite sides of said peak, a spindle member mounted on said handle to be movable radially relative to said pivot axis, said spindle member engaging said 0am track to be moved thereby from one valley across said peak to the other valley upon movement of said operating handle between said first and second rest positions, said spindle member yieldably limiting the extreme positions of said handle upon engagement of said spindle member with the curved second part of one of said arcuate portions, means urging said spindle member away from said pivot axis, switching means within said housing, terminal means for connecting opposite sides of said switching means in a circuit, and means on said handle independent of said member and engageable with said switching means for opening and closing said switching means in response to movement of said handle between said first and second rest positions respectively.

References Cited in the file of this patent UNITED STATES PATENTS 2,807,683 Bettencourt Sept. 24, 1957 2,809,246 Taylor Oct. 8, 1957 FORETGN PATENTS 413,976 Great Britain July 26, 1934 648,875 Great Britain Jan. 17, 1951 489,713 Italy Ian. 26, 1954 

